I feel like I am some kind of misery guts and going against everything everyone else has said, but, you asked, so... Bare Minerals is not as pure as it says it is. It's one of the most chemically-filled mineral makeups you can get. It USED to be very pure, but they changed the formula as they grew and became more of a highstreet/retail brand. This fundamental shift from their basic principles caused a big rift in the company, and another company was actually formed by some of the original founders of bare minerals to bring mineral makeup back to its pure and chemical-free roots.
I am surprised at some of the comments above as I know quite a few people who have sensitive skin and so have ended up having very bad reactions to it, including my best friend who was supposed to be having bare minerals as her bridal makeup.
I honestly am not trying to put them down for no reason, just sharing what I know.